EngineeringFormulaFlow Rate Conversion
Convert US gpm to L/min
1 US gpm = 3.7854 L/min
Pump and pipe flow specs from US manufacturers are rated in US gallons per minute; European and most other international pump curves are rated in liters per minute.
1 US gallon equals 3.78541 liters, so 1 US gpm = 3.78541 L/min directly - the time base (per minute) is already shared.
A typical residential well pump rated at 10 US gpm delivers about 37.9 L/min.
Reference Table
| US gallons per minute (US gpm) | liters per minute (L/min) |
|---|---|
| 1 | 3.7854 |
| 5 | 18.927 |
| 10 | 37.854 |
| 25 | 94.635 |
| 50 | 189.27 |
| 100 | 378.54 |
Used In These Calculators
Frequently Asked Questions
Is a US gallon the same as an imperial gallon?
No, and this is a genuinely common source of error - a US gallon (3.78541 L) is meaningfully smaller than an imperial (UK) gallon (4.54609 L), about a 20% difference. This conversion uses the US gallon specifically; a pump spec from a UK or Commonwealth manufacturer using imperial gallons needs a different factor.
Does GPM alone tell you how a pump will perform?
No - GPM (or L/min) describes flow rate at a given operating point, but a pump's actual output depends on the pressure or head it's working against too. A pump's performance curve, not a single GPM number, is what shows how flow rate changes as head or pressure increases.
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